Influence of Neodymium Addition on the Microstructure, Mechanical and Thermal Properties of Mg-Si Alloys

The present work aims to investigate the influence of neodymium addition on the microstructure, mechanical and thermal properties of Mg-Si alloys. Different proportions of (0.3, 0.6, 0.9 and 1.2 wt.%) Nd has been added to the hypo (Mg-1.15Si) and hypereutectic (Mg-6Si) alloys. The microstructural studies reveal that the Nd additions change the size and morphology of Mg-halos in the hypoeutectic Mg-Si alloy. In the hypereutectic alloy, the Nd additions considerably reduce the size of the primary Mg2Si phase besides, modifying the Mg2Si morphology from a coarse dendritic to a polyhedral shape. The amount of Nd required for the optimal modification of both alloys is experimentally determined. Increase in mechanical properties obtained with Nd addition is correlated with the microstructural refinement. To understand the microfracture mechanism, the SEM analysis has been carried out. (C) 2013 The Authors. Published by Elsevier Ltd.